Chapter 12: Homeostasis

Define homeostasis.

It is the "maintenance of constant internal environment".

What conditions are required for homeostatic control?

Conditions required are; "stimulus", "receptor", "corrective mechanism" and "negative feedback".

What mechanism is used to achieve homeostasis?

Mechanism used is "negative feedback" mechanism.

How does your body react after a meal rich in sugar to achieve normal conditions?

Normal blood glucose concentration is achieved by:

• An increase in blood glucose concentration (stimulus).
• "Pancreas is stimulated" (receptor).
• Pancreas will start secreting "more insulin"; to "convert glucose to glycogen" in liver (corrective mechanism).
• Normal condition achieved.

What is the role of insulin in the body?

It decreases "blood glucose concentration".

What is the role of glucagon in the body?

It "increases blood glucose concentration" by converting glycogen to glucose.

Give 2 processes involving the skin that cool the body down.

2 processes involved are; "sweating" and "vasodilation". When the body sweats it cools down by evaporation and in vasodilation blood starts to flow closer to the surface of the skin where it can cool.

Give 3 processes that work to keep the body warm.

3 processes involved are; "vasoconstriction", "shivering" and "erection of hairs on the skin".